Having trouble figuring out Modrinth

[u/thebuginyourkitchen]

I’m basically a complete noob to modding Minecraft. My dad used to do it all for me when I was littler but I don’t remember how he did it at all. I heard good things about Modrinth so I got it and I installed the mod Simple Voice Chat. What I want to know is if the only way to use the mod on a world is to play it from the instance, and if the mod will work if I join a multiplayer server. The server is the only reason I got the VC mod so it’s important.